CN102026332B - Routing method for wireless sensor networks in building automation system (BAS) - Google Patents

Abstract

The invention discloses a routing method for route wireless sensor networks in a building automation system (BAS) on the basis of analysis of BAS features, which solves the problems of complex network structure and difficult network assignment in the BAS and local minimum points in local control networks. The method comprises the following steps of: firstly, dividing a given network topology into trunk networks and local control networks; secondly, putting forward a new address allocation mechanism to solve the problem that the ZigBee protocol can not meet distributed address allocation; and thirdly, putting forward a GREFA routing method based on surface routing to solve the problem that greedy routing based on location information in local control networks has local minimum points. Simulation results show that the routing method has high reliability, real-time performance and low power consumption, and effectively solves the problem of adaptability of routing methods in the BAS.

Description

The method for routing of wireless sensor network in the building automation system

Technical field

The present invention relates to the method for routing of wireless sensor network in the building automation system (BAS), belong to the wireless sensor network technology field.

Background technology

It is low that wireless sensor network (WSN) technology is installed expense with it, can carry out data acquisition in the place of being inconvenient to connect up, and easily advantage such as reconstruct and easy upgrading and gaining great popularity has become one of mainstream technology of building automation system (BAS).And as the routing issue of one of WSN key technology, the research that also is subjected to large quantities of scholars is paid close attention to.In the wireless sensor network of BAS, solve the network configuration characteristic that the route assignment problem will be considered BAS itself usually.The nodal information redundancy is the principal element that influences network congestion degree and network processes speed, and the redundancy of nodal information is higher among the BAS; Node energy consumption is to influence the whole energy consumption of network and the principal element of life cycle; The reliability of transmission is one of the key factor that influences the quality of data of network collection.Therefore, how under the high situation of BAS nodal information redundancy, the problem that solves node energy consumption and life cycle, transmission reliability has become a hot research direction of wireless sensor network among the BAS.

BAS is one of wireless sensor network technology main field of application, but does not also have the special Routing Protocol that designs at BAS at present.The ZigBee agreement is a kind of standardization agreement of extensive use in wireless sensor network.Yet but there is the expansion restriction in it, because its " distributed address distribution " can not distribute the address for all nodes, especially in backbone network.And, spreading unchecked route and cause more energy consumption, this will exhaust the energy of battery, also reduce the life span of network.

Therefore routing issue is one of problem demanding prompt solution among the BAS, and its research has great importance.

Summary of the invention

Reliability and the high problem of energy consumption at method for routing in the existing BAS wireless sensor network, the present invention analyzes the characteristic of BAS wireless sensor network, and the wireless sensor network routing method of a kind of BAS of being suitable for has been proposed, reach and not only guarantee transmission reliability but also energy efficient, and solve effectively that the network address is distributed and the purpose of local smallest point.

According to technical scheme provided by the invention, the method for routing of wireless sensor network is in the described building automation system: given wireless senser networking topology is divided into backbone network and local control network, makes that the space of each sealing can communicate by backbone network in the building; In backbone network, adopt the static routing method, in local control network, adopt the Routing Protocol in the wireless sensor network; And distribute bunch address and node address respectively for leader cluster node and ordinary node in the backbone network; According to bunch address and the node address of backbone network, for route requests is selected the static routing method; In local control network, employing is based on the mixing method for routing of greedy method for routing and face method for routing, namely utilize greedy routing algorithm to seek route at source node, after running into local smallest point, employing face route technology by the face border of search barrier, is approached destination node length by length, after jumping out local smallest point, continue to carry out greedy method for routing; The route requests of different floor gaps can not directly be set up, and needs to be transmitted by the gateway node of backbone network.

The distribution method of described bunch of address is: bunch address C_ID of each routing node of backbone network manually is set in network configuration, and definition distributes the side-play amount Cskip (d) of address:

$\mathrm{Cskip}\left(d\right)=\frac{1-{\mathrm{Cm}}^{\mathrm{Lm}-d}}{1-\mathrm{Cm}}$

Wherein, d is that present node is to the degree of depth of telegon; Cm is the maximum son node number that a node can have; Lm is depth capacity;

To the multitiered network structure of building automation system, bunch address of leader cluster node is that 0, the i layer submanifold address is by following distribution: C_ID _i=C_ID+ (i-1) * Cskip (d)+1; In network configuration, all nodes in same bunch have identical bunch address C_ID.

The distribution method of described node address is: node address N_ID distributes from a bunch head, and the N_ID of bunch head is 0, and it can the broadcast beacon bag, after a node that does not have a N_ID receives beacon from same cluster knot point, sends adding information for the beacon sender; The N_ID allocation step:

(1) the leader cluster node s (C_ID of transmission beacon _s, N_ID _s) in cluster, receive adding information, and according to the intensity that receives signal, by descending they are recorded in the table;

(2) node address of leader cluster node is arranged to N_ID _s, the node that adds for each request distributes the address then, and the address assignment principle is: add 1 on the basis of previous address in order;

(3) after the address assignment of all bunches member node finishes, leader cluster node sends mark with beacon and transfers to last node in the table, go on the air beacon and repeat preceding step and have the node address N_ID of oneself up to all bunches member in same bunch of this node.

After distributing bunch address C_ID and node address N_ID, the static routing method in the building automation system backbone network is: the address of hypothesis goal node D is F_ID _DC_ID _DN_ID _D, the address of present node A is F_ID _AC_ID _AN_ID _AWhen present node A receives a bag that mails to destination node D,

(1) if C_ID _D=C_ID _A, they belong to same bunch; Present node A is sent to neighbor node u with this bag, bunch address C_ID of node u _UEqual bunch address C_ID of destination node _D, and make | N_ID _U-N_ID _D| minimum;

(2) if C_ID _A＜C_ID _D＜C_ID _A+ Cskip (d-1), destination node D are sent to a next one bunch packets of information in the submanifold of present node A

Present node A sends packet to next bunch then, repeats the first step;

(3) otherwise, destination node D is father node, or with present node A in same subtree; Present node A sends bag by its bunch head to father's cluster knot point, repeats the first step and arrives destination node D until bag.

When breaking down in the local control network, upstream node will be sought the new route of leading to destination node by described mixing method for routing again, before beginning to seek new route, upstream node at first is stored to packet in the sequence, after new route finds, again the packet in the sequence is sent to destination node.

In described mixing method for routing, method from source node to destination node that seek a reliable route from is:

(1) at first, move greedy routing algorithm, judge whether to arrive destination node or local smallest point;

(2) if arrive destination node, then stop algorithm; If just arrive local smallest point, then at local smallest point place, send detection packet by the border along barrier and search for transmission path, until jumping out local smallest point;

(3) after jumping out local smallest point, continue greedy method for routing, if run into local smallest point again, according to the step process in second step.

Sending detection packet on described border along barrier and search for transmission path, is centered by local smallest point, radius of initialization

Circle, λ wherein ₀Be a constant,

It is the vector distance that source node arrives destination node, from local smallest point, send detection packet in the counterclockwise direction to its next-hop node, if this node is positioned at the circle that radius is R, then continue to send detection packet to the next-hop node of this node, if this node not in radius is the circle of R, then is back to local smallest point; In like manner send detection packet along clockwise direction to the next-hop node of local smallest point; Finally obtain one in radius is the circle of R, along obstacles borders, and jump out the path of local smallest point.

The method for routing of wireless sensor network among the BAS that the present invention proposes can be avoided BAS under the double-layer network structure network address to occur and exhaust local smallest point problem with greedy algorithm.Adopt this method that the routing issue among the BAS has been carried out simulation analysis effectively, on the NS2 platform, can realize the emulation to the method for routing of ZigBee agreement method for routing and the present invention's proposition, obtain the final effect of two kinds of algorithms, as command traffic, packet loss, average packet time delay.According to these performance parameters, not only can assess the superiority of each algorithm, can also contrast various algorithms, draw which algorithm and be more suitable for the network with BAS.By the prioritization scheme that this method is chosen, can be implemented among the BAS reliably, in real time, transport service with low power, thereby make whole building realize seamless link and automation thereof.

Description of drawings

Fig. 1 is the logical network schematic diagram.

Fig. 2 is the double-layer network structural representation among the BAS.

Fig. 3 is network topology model, and s is source node, and d is destination node, runs into local smallest point problem at the u node.

Fig. 4 is the backbone network schematic diagram in the corridor.

Fig. 5 is six kinds of emulation topological environmentals.

Fig. 6 is the order expense comparison diagram of ZBRP and GREFA.

Fig. 7 is the packet loss comparison diagram of ZBRP and GREFA.

Fig. 8 is the average delay comparison diagram of ZBRP (ZigBee routing) and GREFA route.

Fig. 9 is the method for the invention schematic diagram.

Embodiment

For the BAS system to complexity carries out rational route planning, at first, we carry out the classification division to the network configuration of BAS, are divided into: backbone network and local control network.Secondly, the problem at address assignment deficiency in the backbone network has proposed a kind of address allocation scheme, thereby has solved the routing issue in the backbone network effectively.Again, local control network is made up of a plurality of wireless sensor networks, and the wireless sensor network routing algorithm of position-based information mainly contains: 1, greedy routing algorithm: be a kind of energy-saving routing mechanism.S thinks access node d.Any possible in, routing mechanism is attempted greedy route bag, this is by sending information to the nearest neighbor node from destination node d at each intermediate node.Yet this algorithm may run into a local smallest point problem, and namely at a certain node u, its any one neighbor node all oneself arrives the distance of destination node d than it to the distance of destination node d, thereby the phenomenon of route occurs seeking.2, face routing algorithm: after running into barrier, the process that data are transmitted along the border of barrier.It can solve local smallest point problem, still too late greedy routing algorithm on efficiency.So on the basis in conjunction with greedy routing mechanism and face routing mechanism, proposed a kind of mixing routing algorithm (GREFA), thereby solved the local smallest point problem in the local control network effectively.

The Performance Evaluation that solves method for routing is the important step of research routing issue, and the microcomputer modellings that adopt carry out simulation analysis more at present, and the routing issue that the present invention is directed to the BAS network has carried out modeling and performance simulation analysis.

The technical solution used in the present invention is: 1, according to the topology of particular network, divide the double-layer network structure; 2, according to the characteristic of the network of different levels, provide different routing mechanisms; 3, according to the source and destination node of business to business routing on the double-layer network structure; 4, handle all business after, the route of setting up is carried out performance evaluation.As shown in Figure 9, this technical scheme is specially: given network topology is divided into backbone network and local control network, has solved the network complexity problem under the building large scale structure, make that the space of each sealing can communicate by backbone network in the building; According to the network configuration characteristic of backbone network, in backbone network, adopt the static routing method, in LCN (local control network), then adopt the Routing Protocol in the WSN network; And distribute a bunch address (C_ID) and node address (N_ID) respectively for leader cluster node and ordinary node in the backbone network; According to bunch address and the node address of backbone network, for route requests is selected the static routing method; In local control network, adopt the mixing method for routing based on greedy method for routing and face method for routing.The route requests of different floor gaps can not directly be set up, and needs to be transmitted by the gateway node of backbone network.

I, because the irregular and closure of backbone network, ZigBee distributed network address assignment can cause in the BAS backbone network network address to distribute the problem that exhausts.For fear of this problem, the present invention adopts the tree address assignment, for Backbone network is stored from bunch tree address of that acquisition of CH by structure of definition.For emulation for simplicity, the tree address each field be set as 1 byte.Network address structure is as shown in the table.

F_ID (byte 1)	C_ID(1)	N_ID(1)
			The floor identification symbol	Bunch identifier	Node identifier

F_ID manually is set in network configuration.What we paid close attention to is the assignment problem of C_ID and N_ID.

1.C_ID distribute

This is similar with the distributed network address assignment among the ZigBee.The C_ID of each routing node of backbone network manually is set in network configuration.The same with ZigBee, we define the side-play amount Cskip (d) that distributes the address like this.

$\mathrm{Cskip}\left(d\right)=\frac{1-{\mathrm{Cm}}^{\mathrm{Lm}-d}}{1-\mathrm{Cm}}$

D is that present node is to the degree of depth of telegon; Cm is the maximum son node number that a node can have; Lm is depth capacity, and Lm=5 for example is set, Cm=2, and the result is as shown in fig. 1.

Come to distribute C_ID for all nodes among Fig. 2 with Cskip mechanism.The C_ID of node s is 0.The degree of depth of each node is d in Fig. 1, if a bunch address is C_ID, following distribution is pressed in its i layer submanifold address so:

C_ID _i＝C_ID+(i-1)*Cskip(d)+1

In network configuration, all nodes in same bunch have identical C_ID.

2.N_ID distribute

The distribution of N_ID is from a bunch head, and the N_ID of a bunch CH is 0, and it can broadcast packet, and after a node that does not have a N_ID received beacon from same cluster knot point, it just sent and adds (JOIN) information to beacon (Beacon) sender.

The N_ID allocation step:

1) beacon transmit leg s (C_ID _s, N_ID _s) in cluster, receive adding information, and according to the intensity that receives signal, by descending they are recorded in the table.

2) node address of leader cluster node is arranged to N_ID _s, being each the requesting node distribution node address in the table then, the address assignment principle is: add 1 according to the order in the table on the basis of previous address;

3) wait after the address assignment end of all bunches member node, leader cluster node sends mark with beacon and transfers to last node in the table, go on the air beacon and repeat preceding step and have the node address N_ID of oneself up to all bunches member node in same bunch of this node.

Following table is some addresss of node among Fig. 4.Suppose that they are at ground floor upstairs.

Node	The address	Node	The address
				T	1.32.0	U	1.1.0
G	1.32.1	F	1.1.1
				I	1.32.2	H	1.1.2
M	1.32.3	J	1.1.3

Now, all nodes of backbone network have unique network address in the whole building.This with the IP address class in the internet seemingly.Above-mentioned address allocation scheme designs for static routing mechanism in the backbone network.After distributing C_ID and N_ID, provided the static routing algorithm in the BAS backbone network: the address of hypothesis goal node D is (F_ID _DC_ID _DN_ID _D), the address of present node A is (F_ID _AC_ID _AN_ID _A).When present node A receives a bag that mails to destination node D,

1) if C_ID _D=C_ID _A, they belong to same bunch.Present node A is sent to neighbor node u with this bag, so bunch address C_ID of node u _UEqual bunch address C_ID of destination node _D, and make | N_ID _U-N_ID _D| minimum;

2) if C_ID _A＜C_ID _D＜C_ID _A+ Cskip (d-1), destination node D is sent to a next one bunch packets of information in the submanifold of present node A so

Present node A sends packet to next bunch then, repeats the first step.

3) otherwise, destination node D or be father node, otherwise be with present node A in same subtree.Present node A sends bag by its a bunch CH to father's cluster knot point, repeats the first step and arrives destination node D until bag.

Algorithm is the network address in the dependency network only, the discovery of route and safeguard and do not need extra order expense.Because all nodes all are active, they are not easy necrosis or fault; If break down, then should upgrade network by reconfiguring some new nodes at malfunctioning node, so in backbone network, should place some secondary nodes more.

Above-mentioned routing mechanism only is applicable in the backbone network of first floor.For multilayer communication, we need install some bridge nodes (perhaps other are local easily) at stair, make the network interconnection of two interlayers.Deployment and the configuration of bridge are similar to Local Area Network.This is outside our research range.Communication process is as follows:

1) bag at first is sent to bridge node at current floor by above-mentioned static routing algorithm.

2) its neighbor table of bridge node inspection and they are sent to next bridge node till the bridge node that arrives the purpose floor.

3) be sent to destination node by above-mentioned static routing algorithm bag.

II, solving among the BAS behind the method for routing of backbone network, and proposing a kind of mixing method for routing (GREFA) based on greedy route and face route for local control network.This method for routing has solved the local smallest point problem that greedy method for routing exists in the local control network.At first, utilize greedy routing algorithm to seek route at source node; Secondly, after running into local smallest point, adopt the face route technology, this technology is approached destination node length by length by the face border of search barrier; Again, after jumping out local smallest point, for energy efficient, continue to carry out greedy method for routing.

According to the network topology among Fig. 3.Node s is source node, and node d is destination node.What dotted line was represented is two barriers.We suppose that the transmission range of all nodes is identical before route describing.For example, s will insert d.The GREFA routing algorithm is operated in greedy pattern from s.But run into local smallest point problem at node u.The GREFA route switches to towards route pattern, and beginning is along obstacles borders search transmission path.

GREFA algorithm parameter: λ ₀, λ, R, C ₁, C ₂

Be the radius of circle centered by node d, wherein λ ₀Be a constant,

It is the vector distance that source node arrives destination node; λ is constant; C ₁And C ₂Be two counters, follow the tracks of in the access number when front route stage node, wherein, C ₁Expression is to the distance node number nearer than local smallest point of destination node, C ₂Expression is to the distance node number more farther than local smallest point of destination node.

In commission, λ ₀, the selection of λ should and remain unchanged prior to the algorithm operation.Local control network network constant definition is as shown in the table.

The greedy route of Step1:() the greedy routing algorithm of operation is up to arriving d or local smallest point.If the latter then continues Step2.

Step2:(is towards route) u is local minimum node.It will search for reliable transmission path by sending detection packet along obstacles borders.At first, circle centered by d of node u initialization

Node u sends bag at first in the counterclockwise direction to node f, but the next-hop node p of node f is on circle.So return node u, node u is sent to node t in the clockwise direction.Continue this operation, until arriving node h.At node h, C ₁=2, C ₂=1, C ₁＞C ₂So algorithm can be back to greedy route up to arriving node d.

But sometimes, even local smallest point still can meet circle after clockwise search.In this case, we must enlarge the circle radius to R=λ R, repeat Step2 then.If this situation takes place to surpass three times, algorithm just thinks that destination node is unreachable so.

Node on data channel breaks down, and upstream node will start the GREFA route discovery processes again, seeks the new transmission path that leads to destination node.Before starting new route discovery processes, node at first is stored to packet in the sequence.After route finds, again the bag in the sequence is sent to destination node.This mechanism has guaranteed the high reliability of route.

Fig. 5 is six kinds of different emulation topological environmentals setting up at the NS2 platform.On these six kinds of network topologies, the routing algorithm in GREFA and the ZigBee agreement is carried out performance relatively.

Fig. 6 is at different network topologies, and the performance that the GREFA that the present invention is proposed and the ZBRP method for routing of ZigBee agreement carry out relatively.As can be seen, the order expense of ZBRP is high more a lot of than GREFA, and increases fast along with the increase of network size.This is because ZigBee sends the frequency of Hello bag and route discovery expense than higher.On the contrary, the order expense of GREFA is lower, and along with the network size is constant substantially.This is because its Hello bag transmission frequency and route discovery expense are lower.Among the figure, abscissa is represented network size or number of nodes; Ordinate represents to order the quantity of bag, has reflected the size of order expense.

By the performance comparison on this analogue system as can be known, under identical simulated environment, the order expense of GREFA is lower than ZBRP.This shows that the method for routing that the present invention proposes can solve the routing issue among the BAS effectively.

What Fig. 7 represented is the packet loss of ZigBee AODVjr and GREFA algorithm.Obviously, under all-network the packet loss of ZBRP than GREFA height.When number of network node rose to 30, the transfer rate of ZigBee was lower than 90%.Main cause is the increase along with the node number, bigger competition and conflict can occur at the MAC layer, and the control command bag of ZigBee is more than GREFA.

In addition, along with the increase of network size, the packet loss of two kinds of algorithms can present ascendant trend.This is because for any one routing algorithm, and competition and conflict all are to become big along with the increase of network size.The packet loss of GREFA under 6 kinds of network topologies all is lower than 6%, and this shows that it has more reliability than ZigBee AODVjr.

What Fig. 8 represented is the average delay of ZBRP (ZigBee routing) and GREFA route.The GREFA average delay is lower than ZigBee.This is because GREFA can guarantee with minimum jumping figure to be that every data paths finds a best route.And, because the order expense of GREFA is low and conflict is few, make its route finding process than ZigBee more quickly and effectively.

At last, the method for routing in backbone network among the BAS and the local control network combined at the NS2 platform move, draw that the minimum average transfer rate of WSN network can reach 80% among the BAS, satisfy the transfer rate requirement of WSN among the large-scale BAS; The maximum average packet time delay of WSN network is 102.25ms among the BAS, and this can meet its delay requirement for heavy construction.The main cause of method for routing superior performance provided by the invention is:

1) according to positional information, the GREFA route transmits RREQ information to destination node.Therefore, compare with other routing mechanism, it has reduced the delay of route discovery.

2) static tree routing mechanism only relies on the hierarchical tree address, do not need route finding process, so its bag propagation delay is very short.

3) the order expense of these two kinds of algorithms is very low, so it has reduced conflict, and then has reduced heavy-route and bag retransmission processes.

To sum up, the present invention is on the basis of having analyzed the BAS network characteristic, proposed a kind of double-layer network structure, and proposed the network route method of a kind of BAS of being applicable in this network configuration, solved the complicated network structure in BAS, be difficult for the problem of distribution network address and local smallest point.

Claims (7)

1. the method for routing of wireless sensor network in the building automation system is characterized in that: given wireless senser networking topology is divided into backbone network and local control network, makes that the space of each sealing can communicate by backbone network in the building; In backbone network, adopt the static routing method, in local control network, adopt the Routing Protocol in the wireless sensor network; And distribute bunch address and node address respectively for leader cluster node and ordinary node in the backbone network; According to bunch address and the node address of backbone network, for route requests is selected the static routing method; In local control network, employing is based on the mixing method for routing of greedy method for routing and face method for routing, namely utilize greedy routing algorithm to seek route at source node, after running into local smallest point, employing face route technology by the face border of search barrier, is approached destination node length by length, after jumping out local smallest point, continue to carry out greedy method for routing; The route requests of different floor gaps can not directly be set up, and needs to be transmitted by the gateway node of backbone network.

2. the method for routing of wireless sensor network in the building automation system as claimed in claim 1, the distribution method that it is characterized in that described bunch of address is: bunch address C_ID of each routing node of backbone network manually is set in network configuration, and definition distributes the side-play amount Cskip (d) of address:

$\mathrm{Cskip}\left(d\right)=\frac{1-{\mathrm{Cm}}^{\mathrm{Lm}-d}}{1-\mathrm{Cm}}.$

Wherein, d is that present node is to the degree of depth of telegon; Cm is the maximum son node number that a node can have; Lm is depth capacity;

To the multitiered network structure of building automation system, bunch address of leader cluster node is that 0, the i layer submanifold address is by following distribution: C_ID _i=C_ID+ (i-1) * Cskip (d)+1; In network configuration, all nodes in same bunch have identical bunch address C_ID.

3. the method for routing of wireless sensor network in the building automation system as claimed in claim 2 is characterized in that the distribution method of described node address is:

Node address N_ID distributes from a bunch head, and the N_ID of bunch head is 0, and it be the broadcast beacon bag, after a node that does not have a N_ID receives beacon from same cluster knot point, sends adding information to the beacon sender; The N_ID allocation step:

(1) the leader cluster node s (C_ID of transmission beacon _s, N_ID _s) in cluster, receive adding information, and according to the intensity that receives signal, by descending they are recorded in the table;

(2) node address of leader cluster node is arranged to N_ID _s, the node that adds for each request distributes the address then, and the address assignment principle is: add 1 on the basis of previous address in order;

(3) after the address assignment of all bunches member node finishes, leader cluster node sends mark with beacon and transfers to last node in the table, go on the air beacon and repeat preceding step and have the node address N_ID of oneself up to all bunches member in same bunch of this node.

4. as the method for routing of wireless sensor network in claim 2 or the 3 described building automation systems, it is characterized in that after distributing bunch address C_ID and node address N_ID, the static routing method in the building automation system backbone network is: the address of hypothesis goal node D is F_ID _D.C_ID _D.N_ID _D, the address of present node A is F_ID _A.C_ID _A.N_ID _AWhen present node A receives a bag that mails to destination node D,

(1) if C_ID _D=C_ID _A, they belong to same bunch; Present node A is sent to neighbor node u with this bag, bunch address C_ID of node u _UEqual bunch address C_ID of destination node _D, and make | N_ID _U-N_ID _D| minimum;

(2) if C_ID _A＜C_ID _D＜C_ID _A+ Cskip (d 1), destination node D are sent to a next one bunch packets of information in the submanifold of present node A

Present node A sends packet to next bunch then, repeats the first step;

(3) otherwise, destination node D is father node, or with present node A in same subtree; Present node A sends bag by its bunch head to father's cluster knot point, repeats the first step and arrives destination node D until bag.

5. the method for routing of wireless sensor network in the building automation system as claimed in claim 1, it is characterized in that when breaking down in the local control network, upstream node will be sought the new route of leading to destination node by described mixing method for routing again, before beginning to seek new route, upstream node at first is stored to packet in the sequence, after new route finds, again the packet in the sequence is sent to destination node.

6. the method for routing of wireless sensor network in the building automation system as claimed in claim 1 is characterized in that in described mixing method for routing, and method from source node to destination node that seek a suitable route from is:

(1) at first, move greedy routing algorithm, judge whether to arrive destination node or local smallest point;

(2) if arrive destination node, then stop algorithm; If just arrive local smallest point, then at local smallest point place, send detection packet by the border along barrier and search for transmission path, until jumping out local smallest point;

(3) after jumping out local smallest point, continue greedy method for routing, if run into local smallest point again, according to the step process in second step.

7. the method for routing of wireless sensor network in the building automation system as claimed in claim 6 is characterized in that sending detection packet on described border along barrier searches for transmission path, is centered by local smallest point, radius of initialization

Circle, λ wherein ₀Be a constant,

It is the vector distance that source node arrives destination node, from local smallest point, send detection packet in the counterclockwise direction to its next-hop node, if this node is positioned at the circle that radius is R, then continue to send detection packet to the next-hop node of this node, if this node not in radius is the circle of R, then is back to local smallest point; In like manner send detection packet along clockwise direction to the next-hop node of local smallest point; Finally obtain one in radius is the circle of R, along obstacles borders, and jump out the path of local smallest point.

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